Is a boar bristle brush worth it?

I have fine and thin hair that easily gets greasy and that has hardly any volume. When I leave my hair open, it’ll hang down in strings after a bit…I read that boar bristle brushes spread your hair’s natural oils down to the ends as well and makes them shiny and nice.

Has anyone tried this? Does it just make the hair greasier and flatter?

I’m debating whether buying one of those Mason Pearson brushes is worth it when I go to the UK.